Sciencemadness Discussion Board

toluene --> benzaldehyde

 Pages:  1  ..  3    5    7

questions - 12-2-2011 at 23:31

Quote: Originally posted by Melgar  
Benzaldehyde can be made pretty easily by mixing styrene, acetone, and a small amount of water (like 5% of the quantity of acetone) then running ozone into the mixture, which should ideally be kept as cold as possible to prevent the evaporation of acetone. This method of ozonolysis seems to only produce good yields with terminal alkenes such as styrene though.


Hey, I liked your method of making benzaldehyde from styrene, acetone water and ozone.

Have you actually tried this method?
And if you have tried this method, did it work well?

Melgar - 15-2-2011 at 17:18

Quote: Originally posted by questions  
Quote: Originally posted by Melgar  
Benzaldehyde can be made pretty easily by mixing styrene, acetone, and a small amount of water (like 5% of the quantity of acetone) then running ozone into the mixture, which should ideally be kept as cold as possible to prevent the evaporation of acetone. This method of ozonolysis seems to only produce good yields with terminal alkenes such as styrene though.


Hey, I liked your method of making benzaldehyde from styrene, acetone water and ozone.

Have you actually tried this method?
And if you have tried this method, did it work well?

I have, and it works pretty well. You make a solution of 95% acetone and 5% water, then mix in the styrene (I used about a quarter styrene) and run ozone through it. The two main problems with this method are 1) the acetone tends to evaporate, so you need to constantly refill it, and 2) you need however many moles of ozone as you have styrene, and since an ozone generator typically outputs 2-3 percent ozone, this can take a while. You can minimize lost acetone by keeping the reaction really cold, but unless it's winter, that can be hard to do. So really, this reaction works best in the winter. :)

Also, the first time you do this reaction, do it with maybe 10 mL of styrene, just so you get an idea of how long it takes to ozonolyze it. I started with like 250 mL and it took way too long and I was never able to finish.

The article that describes this method is here:
http://pubs.acs.org/doi/abs/10.1021/jo800323x

I have the full text pdf if you can't get it yourself.

The nice thing about this is purification is easy, if you're not a stickler for purity. Just heat it to like 150C in a narrow-neck boiling flask and leave it there for a while and the styrene and acetone and water will boil away leaving mostly benzaldehyde.

benzaldehyde from ozone

questions - 15-2-2011 at 19:30

I read on the wikipedia that ozone can be produced in the laboratory as shown on the link below.

Laboratory productionIn the laboratory, ozone can be produced by electrolysis using a 9 volt battery, a pencil graphite rod cathode, a platinum wire anode and a 3 molar sulfuric acid electrolyte.[45] The half cell reactions taking place are:

3 H2O → O3 + 6 H+ + 6 e− (ΔEo = −1.53 V)
6 H+ + 6 e− → 3 H2 (ΔEo = 0 V)
2 H2O → O2 + 4 H+ + 4 e− (ΔEo = −1.23 V)
In the net reaction, three equivalents of water are converted into one equivalent of ozone and three equivalents of hydrogen. Oxygen formation is a competing reaction.

It can also be prepared by applying 10,000-20,000 volts DC to dry O2. This can be done with an apparatus consisting of two concentric glass tubes sealed together at the top, with in and out spigots at the top and bottom of the outer tube. The inner core should have a length of metal foil inserted into it connected to one side of the power source. The other side of the power source should be connected to another piece of foil wrapped around the outer tube. Dry O2 should be run through the tube in one spigot. As the O2 is run through one spigot into the apparatus and 10,000-20,000 volts DC are applied to the foil leads, electricity will discharge between the dry dioxygen in the middle and form O3 and O2 out the other spigot. The reaction can be summarized as follows:[6]

3 O2 — electricity → 2 O3

Do you think that this is something I could set up in my garage?

If so do you think that the yeilds of ozone will be good enough for our pures of making benzaldehyde via your styrene method?

mnick12 - 15-2-2011 at 19:42

HV does indeed produce ozone, have you ever messed around with a moniter flyback transformer?

Two things worth mentioning, one ozone is pretty toxic and you really dont want " concentrated" ozone. And secondly I am pretty sure the intermediate in this reaction is an ozonide which can be very unstable past certain tempuratures, so make sure you keep it cool!

Sedit - 15-2-2011 at 19:44

You could use a Neon sign transformer or an oil burner transformer. The later has a built in rectifing circuit which is nice. These output anywhere from 10k-20k at around 24-45MA. The voltage can be kicked up rather easy by filling wine bottles with salt water and a layer of oil on top. Place a coat hanger down thru the cork and use this as one terminal of a capacitor. Place the salt water filled bottle into a small cooler also filled with salt water and oil. A wire placed into this solution will act as the other size of the capacitor. The only theoretical limit to the voltage is the amount of bottles you have each acting as a capacitor in its own right. Take care with this capacitor because even though it appears simple it can kill you if your not careful. I was hit by it one time and needless to say I didn't play with it for a few months after that slowly building up my nerve to get near it again.

madcedar - 16-2-2011 at 00:22

Hello Melgar

Can you please post the pdf of the "Ozonolysis in Solvent/Water Mixtures: Direct Conversion of Alkenes to Aldehydes and Ketones" in this thread for those of us without access.

Kind Regards
Rod

Quote: Originally posted by Melgar  

I have the full text pdf if you can't get it yourself.

thermolysis of polystyrene to styrene

madcedar - 16-2-2011 at 06:00

Styrene can be obtained from polystyrene at temperatures approaching 500 degrees and preferably under vacuum.

http://www.ncbi.nlm.nih.gov/pubmed/18032014

Also at lower temperatures by using a sulphate catalyst if you are a person who believes patents. Please refer to the short 30 page :o attachment.

Attachment: pat6380448 Method for recovering styrene monomer from polystyrene resin by using a catalyst.pdf (938kB)
This file has been downloaded 953 times

Melgar - 17-2-2011 at 06:49

Here it is. Not sure if this is supposed to be posted in the references forum, but it makes more sense to post it here.

Attachment: ozonolysis.pdf (108kB)
This file has been downloaded 2841 times


madcedar - 17-2-2011 at 07:38

Thanks for that Melgar.

Melgar - 17-2-2011 at 09:38

FYI, I have done this reaction and verified it works, however it would be impossible for me to quantify yields due to my lack of making any precise measurements. It did, however, produce several milliliters of benzaldehyde using a very puny ozone generator, so it's definitely an option.

Everything I've read points toward neon sign transformers as the best electronic source for making ozone generators. If you don't have an old neon sign, they only cost like $30 on ebay, plus the one I got has built-in circuitry to prevent you from frying it in the inevitable case where you short-circuit the thing. It definitely generates lots of ozone when electrify foil on two sides of a piece of glass, but I haven't gotten around to building something that can generate ozone and then pump it through a tube into solution though.

roamingnome - 17-2-2011 at 17:53

Thanks Melgar :o

This looks like a real nugget, a game changer even.

No Lindlar's catalyst nor hydrogen

It deserves its own thread though :( because toluene is not an alkene

I see some nice write-ups already

Melgar - 17-2-2011 at 19:34

Ozonolysis is a really cool type of reaction. They used to use it to figure out the structure of organic molecules because the reaction with C=C bonds is so reliable. Basically, you convert C=C to C=O O=C, ie, break the double bond and put an oxygen on either side. With this method, you're generating two aldehydes, but the other is formaldehyde which evaporates at a really low temperature.

Usually though, it has to be done at a really low temperature and can generate explosive peroxides, but this method gets around that.

But anyway, gotta go, gf is naked and tempting me. :-D

Sedit - 17-2-2011 at 19:47

Na stay where your at, ill go handle that for you. You look like you could use some time to yourself so relax ill be there in a minute.

Melgar - 18-2-2011 at 11:23

I posted an ozone generator design in the technochemistry forum. It's set up for nice high air flow rates, which should maximize ozone production.

BlueChemist - 22-2-2011 at 16:54

Benzaldehyde is used as an industrial/commercial non-oxidising biocide.

roamingnome - 9-3-2011 at 19:13

Thank you blue chemist , it is also used for almond cakes


http://www.videojug.com/webvideo/how-to-dissolve-styrofoam-a...

the sound track is motivational and i love intelligent Asian boys (wait that came out wrong)

anyway my question is about the nature of the styrene in that form. I guess i sorta already know the answer. Some type of unpolymerized amorous blob. but wilst in solution its treatment affected by ozone attack may produce useful syntheons.


References:
Polymer Degradation and Stability
Volume 79, Issue 2, 2003, Pages 297-307
Influence of ozone on styrene–ethylene–butylene–styrene (SEBS) copolymer

bingo...
Oxidative Degradation of Polymers in Presence of Ozone
The main products appear to be aldehydes and ketones in the case of polyethylene, while an ozonide or peroxidic complex, stable at intermediate temperatures, forms during polystyrene ozonization. The activation energy is of the order of 9 kcal. for polyethylene; for polystyrene it is considerably less.
OZONE CHEMISTRY AND TECHNOLOGY
Chapter 26, pp 168–175
Chapter DOI: 10.1021/ba-1959-0021.ch026
Advances in Chemistry, Vol. 21
ISBN13: 9780841200227eISBN: 9780841221680



benzaldehyde from toluene and nickle oxide

questions - 17-3-2011 at 19:18

Has anyone actual tried making benzaldehyde acording to the method Eng. Pat. 22887, 1900 ?

The link is here;

http://v3.espacenet.com/publicationDetails/originalDocument?...

In this method they react 300 parts of toluene with 150 parts of nickle oxide and heat it for 5 to 6 hours and then filter of the nickle compound formed and then use steam to get the benzaldehyde out of the unreacted toluene.

Has anyone actualy tried this method and if so, how much benzaldehyde was actualy made and how much of each reactant was used?

benzaldehyde from nickel oxide

questions - 16-5-2011 at 20:28

I know a guy who said he tried making benzaldehyde acording to the method Eng. Pat. 22887, 1900 and he told me that it doesn't work :(

So that is the end of the nickel oxide and toluene idea.

Benzaldehyde from US3531519

questions - 16-5-2011 at 20:38

What about making benzaldehyde according to US3531519 whereby H2O2, sulfuric acid and copper sulfate is used.

In the literature it states that for a 100ml solution of sulfuric acid, hydrogen peroxide and coppersulfate which is mixed with 100ml of toluene and heated to 90C and stirred, the yeilds of benzaldehyde is 48% :)

This certainly seems promising and easy enough to do, also I like the fact that it states the yeilds, so this means that obviously they have tested it to be able to claim a yeild.

The question is, how long does it take for the toluene to get converted to benzaldehyde?

questions - 19-5-2011 at 20:43

Is there anyone reading this thread?
I've made a couple of posts now and no one has responded.........

Sedit - 19-5-2011 at 20:50

Didn't me and you have this discussion before in another thread?

We are not here for your own personal mental masturbators.... if the patent is that simple stop waiting for us to try it for you and go friggin do it already. If you have not attempted this while waiting for us to respond then you obviously can't perform this process. IE: your becomming a burden on the community by never giving back so please shape up, share on or ship out will ya.

questions - 20-5-2011 at 02:49

Any reply is a good one, so thanks Sedit

questions - 20-5-2011 at 03:01

I've been reading a lot of your disscussions with other people on this site Sedit, and you always seem to be prick. What is with you?

Sedit - 20-5-2011 at 05:53

Its a natural gift I have, it pushes people to experiment instead of just talking about experimenting. It also hopefully will push someone to look more into it because they would see that not only was that patent discussed in this thread but also in one called Toluene oxidation fun started by Polverone.

Read closely in the patent because Copper sulfate and sulfuric acid is not the best candidate here, indeed the best results where yeilded from Iron Sulfate and Nitric acid at 85 degrees C topping off at 74.5% after three hours of reaction time.

Do you realize how much could have been accomplished while you waited for us to reply on if it worked on not?

Attachment: US3531519.pdf (194kB)
This file has been downloaded 1021 times

madcedar - 20-5-2011 at 18:09

Exactly.

Quote: Originally posted by Sedit  
... Do you realize how much could have been accomplished while you waited for us to reply on if it worked on not?


questions - 20-5-2011 at 20:04

Thanks heaps Sedit for bringing the patent to my attention again, more specificaly, thanks for bringing my attention to the nitric acid table as I didn't see this initialy. The yeilds are amazing and all the details of the reaction are revealed, including the reaction time.


Thanks heaps.

Sedit - 21-5-2011 at 08:20

I thought I had everything needed and was going to give this a shot but I seem to have mis-placed my Potassium Nitrate which I was going to use to make some Getto HNO3 and perform a test tube run. 74% yeilds with high selectivity is great if the patent holds to its word.

I don't really want to use Ammonium nitrate which I know I have because i'm concerned about the ammonia cation complexing with any formed Benzaldahyde. Who knows though. It might stabilize it and it might destroy the reaction. It also might not do shit but its not a varible I would like to change the first time performing the reaction.

Sedit - 23-5-2011 at 05:18

I started a little quick and dirty test tube experiment to see if I could detect the slightest smell of BnO but I quickly aborted it for reasons below.

I decided to make some nitric acid using H2SO4 and my ammonia nitrate even though I fear this could mess up the reaction a bit I wanted to try because I was bord. After making some crude nitric acid and adding some Iron sulfate I added some Toluene to it I started to run thru all the possible reactions side reactions ect as normal and quickly realized what I had just done. I had just added Toluene to an unknown concentration of Nitric acid.....

I quickly quenched it with water because of fear that Nitrotoluenes might form and the last thing I wanted to do is have this thing blow up in my face.

Later even with the lowered yeilds im going to start out with just H2SO4/Iron Sulfate/ H2O2 and see where that takes me.

It states a .1 molar concentration of H2O2... What percentage would that be if ya'll don't mind me asking? I never really learned much of concentrations using molar ratios and when I did learn it I would always forget since im more of a w/w or w/v type of guy.

Sedit - 23-5-2011 at 16:46

I have been pouring over this patent and I must say I feel it is legit. It does not have all the babble that BS patents normally have and it reads more like a science paper then a normal patent.

Now I have a question that you all more skilled in the art may be able to answer.

The best yeilds where obtained from Nitric acid at -1 - 1.5 PH and using Ferric sulfate as the source of the Trivalent iron compound. Sulfuric acid produces notibly lower yeilds on the order of around 20% less so it seems likely that the NO3 ion plays a good role. I have been woundering why the patent never uses Ferric Nitrate as the Trivalent iron source as it seems likely that it would produce yeilds on par or possibly greater then that of Sulfates.


Can anyone suggest a reason why they did not use Ferric nitrate? Its synthesis is as simple as Iron in nitric acid and it would mean that there is a coordination of ions instead of mixed sulfate and nitrate ions in the solution.

questions - 23-5-2011 at 21:40

A good question, I'm guessing its because metal sulfates are probably more comon and thats what they had when they were experimienting with the procedure.
I cant see any reason why ferric nitrate wont work either...

benzaldehyde from hydrogen peroxide

questions - 23-5-2011 at 21:48

Hey Sedit, the low yeilds you got with using hydrogen peroxide and sulfuric acid may be because you used the wrong concentrations, esp hydrogen peroxide.

In the patent it say that using sulfuric acid the yeilds should be around 50%...

two questions for you;

1) what yeilds did you get?
2) what were the concentrations?
3) what was the RPM of the stirring you applied?

With toluene type oxidations to benzaldehyde, these three factors are crucial and must be sufficient.

Sedit - 23-5-2011 at 21:59

Umm... you might want to reread everything I wrote to answer your questions. To start with... there are no yeilds?

I will perform these experiments in time and I really want to give HNO3 + Ferric Nitrate a shot but first things first and thats reproducing the patents results.

By all means the best way to go will be to use dilute H2O2 and slowly drip that in. I do not believe that acid concentration is very important just as long as you get it to the desired PH.



[Edited on 24-5-2011 by Sedit]

yeilds of benzaldehyde

questions - 13-6-2011 at 23:43

Hey guys I was just wondering.

I was reading the patent which uses hydrogen peroxide and ferri sulfate with nitric acic in a solution to oxidise toluene to benzaldehyde. They say the yeilds are around 74%. Now on the face of it, it seemed very impressive but I started to wonder exactly how the yeild of 74% was calculated.

Does this mean that with a yeild of 74% I should get 740ml of benzaldehyde out of 1000ml of toluene that I would add to a solution of 1000ml of hydrogen peroxide and ferrisulfate with nitric acid and water?

I'm trying to understand how this yeild is calculated so I can estimate how much product I would get. Can anyone help me with this please?

DJF90 - 13-6-2011 at 23:58

I'm certain that if you read the patent, you'll find:
Quote:

The following examples illustrate the invention. In the examples, the yields given are based on the consumption of hydrogen peroxide on the assumption that 2 molecules of hydrogen peroxide are required to oxidise 1 molecule of the aromatic compound


Maybe you should read the whole patent before jumping into the experimental... you might find something interesting. I've often wondered how many patents are declared false by the amateur community just because the reader has failed to note something that was mentioned in the bulk text.

oh!

questions - 14-6-2011 at 00:44

ouch!!!

The yeilds realy suck then :(

DJF90 - 14-6-2011 at 02:15

No, the yields are 74% - thats generally deemed more than "acceptable". Your issue is that this is not the yield based on toluene. The large excess employed (hydrogen peroxide is the limiting reagent) is likely to minimise further oxidation to benzoic acid.

questions - 14-6-2011 at 20:32

Then why dont they just put alot more ferric sulfate and hydrgen peroxide in it to make more benzaldehyde out of the toluene that is used, because 27g from 1000ml of toluene and 1000ml of solution is terrible?

DJF90 - 14-6-2011 at 22:02

Why don't you try using more concentrated solutions/less toluene and find out?

Pope - 15-6-2011 at 21:19

Going back to the 3rd page, would it be possible to form an adduct with cinnamaldehyde from cassia oil to further purify it from the essential oil to reduce the amount of garbage produced from the reaction.

aduct

questions - 16-6-2011 at 02:43

That would work but after the aduct forms and it precipitates out, you will still need to steam disstill the cinnamic aldehyde out, even if you were to add caudistic soda or even sodium bicarbonate to it.

benzaldehyde from ozonosis of styrene

questions - 16-6-2011 at 20:22

When you say that a typical ozone generator that one could buy from a store would typically produce about 2% ozone, how much ozone PERCENTAGE WISE do you think the method illustrated on the link below would produce?

It is the method where they have glued two pices of steel mesh to either side of a piece of glass and pass 5kV at 1 mA through it.

http://www.bigclive.com/ozone.htm

Melgar - 17-6-2011 at 11:37

I think ozone generators that use air as opposed to pure oxygen are limited to about 2 or 3 percent. As the concentration gets higher it decomposes more quickly via the O3 + O3 = 3O2 reaction.

questions - 24-6-2011 at 21:24

But on that website it says that it will produce a lot of ozone?

MeSynth - 21-8-2011 at 10:08

Quote: Originally posted by questions  
Hey guys I was just wondering.

I was reading the patent which uses hydrogen peroxide and ferri sulfate with nitric acic in a solution to oxidise toluene to benzaldehyde. They say the yeilds are around 74%. Now on the face of it, it seemed very impressive but I started to wonder exactly how the yeild of 74% was calculated.

Does this mean that with a yeild of 74% I should get 740ml of benzaldehyde out of 1000ml of toluene that I would add to a solution of 1000ml of hydrogen peroxide and ferrisulfate with nitric acid and water?

I'm trying to understand how this yeild is calculated so I can estimate how much product I would get. Can anyone help me with this please?


The patent isn't very clear is it?

MeSynth - 21-8-2011 at 10:21

100 mls., of aqueous phase, containing ferric sulphate (pFe=2), hydrogen peroxide (concentration 0.135 molar), and containing 1 gram. equivalent per liter of the acid stated in Table 4 below, were vigerously stirred with 100 mls. of toluene at 85C for 3 hours. Table 4 gives yield of benzaldehyde.

Nitric acid 74.5% yield
Hydrochloric acid 58.5% yield (what the?)
Sulfuric acid 55% yield

----------------------------------------Taken from US3531519

My main question is how much ferric sulphate is used? I do not comprehend (pFe=2) ?

If someone could help me figure out pFe=2 I would be greatful.

DJF90 - 21-8-2011 at 13:04

Read the patent, I recall they define such terms.

MeSynth - 22-8-2011 at 10:43

Ok so I have posted the EXAMPLE above and asked one question but that is not my only question. The example is worded in chemistry code. Most of this code is beyond what I have been able to learn because you tend to only learn this kind of stuff in college (college code kinda stuff). What I think I understand is this...

The aqueous solution has a total volume of 100ml. A solution of ferric sulphate is made with a pFe of 2 and set aside. 0.135 mols of hydrogen peroxide are measured out (4.14 in a syringe). Then a 1 gram equivilent per liter of the acid used is measured out(How do i find the one gram equivalent? ... ) Once the volume of the hydrogen peroxide and the acid has been determined and subtracted from 100 (100ml) you may then take the answer and take that amount from the solution with a pFe of 2 and add it to the beaker or flask then add in the hydrogen peroxide and the acid to reach a total volume of 100ml.


The 2 problems are...

how to make a solution with a pFe of 2?
what is the 1 gram equivalent of sulfuric acid?

[Edited on 22-8-2011 by MeSynth]

here is an example for the gram equivalent of sulfuric acid.

sulfuric acid has a molar mass of 98.078(5) g mol−1, and supplies two moles of hydrogen ions per mole of sulfuric acid, so its equivalent weight is 98.078(5) g mol−1/2 eq mol−1 = 49.039(3) g eq−1.

I am still unsure.



[Edited on 22-8-2011 by MeSynth]

MeSynth - 22-8-2011 at 14:06

Screw it. The example below that one is easier to understand. here it is!

To 100 mls. of a 0.01 molar solution of each of the undermentioned metal ions, added as sulphates, in N sulphuric acid sufficient 65% hydrogen peroxide was added to make the solution 0.1 molar in hydrogen peroxide. This solution was stirred with 100 mls. of toluene for 3 hours at 85 C. the toluene layer was then analysed for benzaldehyde. Table 5 below shows the metal ions used and the yields of benzaldehyde.

ion yield, %
Cr3 36
Ti4 13
Fe3 56

Can someone help me and anyone else who is interested figure out this section of the example... The section in bold is the part in question.

To 100 mls. of a 0.01 molar solution of ferric sulphate in N sulphuric acid sufficient 65% hydrogen peroxide was added to make the solution 0.1 molar in hydrogen peroxide.


EDIT!

Here is the answer to the N sulfuric answer problem. and link

Eq wt x 100/% purity x specific gravity = 49x1000/98x1.84 =27.2
so take 27.2 ml h2so4 and make final volume to one litre = 1N

Read more: http://wiki.answers.com/Q/How_do_you_make_0.02N_sulfuric_aci...





[Edited on 22-8-2011 by MeSynth]

MeSynth - 22-8-2011 at 14:50

I took the liberty. Here is what I came up with...

3.999 gm - ferric sulfate (anhydrous)
2.72 ml - 99% sulfuric acid
3.064 ml - 30% hydrogen peroxide (0.1 mol)
93 ml - DH2O

93ml of DH2O are placed into a 500ml round bottom flask along with a magnetic stir bar. To the H2O is added 4 grams of ferric sulfate (Iron III Sulfate Anhydrous) with stirring. Once the ferric sulfate has dissolved 2.72 ml of sulfuric acid is added slowly with cooling. After the addition of sulfuric acid and the tempurature of the solution is = to room tempurature 3.064 ml of hydrogen peroxide should then be added slowly. After the addition of hydrogen peroxide 100 ml of toluene is added. The mixture is stirred vigerously at 85 C for 3 hours. Remove the toluene layer. Extract benzaldehyde.

Edit... Or the hydrogen peroxide could be added to the toluene and the toluene / hydrogen peroxide solution could be poured in directly since heat at this point is desired.

[Edited on 23-8-2011 by MeSynth]

MeSynth - 28-8-2011 at 12:33

In my last post I said that the conversion of cinnamaldehyde is the best route to benzaldehyde and that I dismissed it due to lack of cinnamaldehyde sources. This was a mistake. I now remember the best method to be the one bellow which is the oxidation of toluene. Very easy to do and quite fun. The hydrogen gas must be scrubbed before being vented. The fact is that everything can be recycled making this the very best. No waste (except for hydrogen thats why you must catch it in a scrub solution). I never got the chance to completely make the benzaldehyde from this reaction due to my beaker being discovered on the side of the house. I discovered it in the trash can. The things I enjoyed most about this where the colors and the smells and the visuals. The swirling of the purple into the white. It is just fun. I will eventually set up a cell but for now this is the post. Bringing it to the end for all you looking to find it easy.

Quote: Originally posted by CycloKnight  
For mass production of benzaldehyde from toluene, the air oxidation of toluene isn't so bad.
Probably alot easier for some than for others.

But if one wanted to go the electrochemical route, here is one way:

I should emphasise that this assumes recycling of the oxidizer. It is kinder to the environment to recycle the oxidizer, but not at all essential. It could be skipped if one were in a hurry, simply by following the steps outlined in the last post to make a suitable quantity of MAA for a single reaction - to make the desired quantity of benzaldehyde. That would shorten the following process greatly.


For 24/7 mass production, there are 9 main steps involved in this process, and some can be carried out at the same time (multi-tasking = good time management!), and others can be combined - more on that later. Here they are:

1) MAA regeneration. May contain many individual cells, working in shift, with say 1 complete every 2 hours.

2) MAA settling. Pour cell mix into acid-proof container container, it must be left undisturbed for at least several hours to allow the MAA to settle out at the bottom. This stage may be made up of a few containers, each holding one batch. When one is added for settling, one is transfered to the next stage.

3) Pour off the saturated acid/MAA. This liquid will now go back to the cell for the next regeneration. You will now be left with a batch equivalent of dark red paste, it will probably still have an inch of liquid on top, it will not interfere.

4) Put into storage container. It would be a good idea to make this container have a several "batch" capacity. So, lets just say that each "step" involves 1Kg batches. Then build up a "buffer" inventory in this storage container of perhaps a few to several Kg of MAA. That way, if an accident occurs or the power goes out, you can still process toluene 'round the clock; this inventory will act as a buffer for your system - though not essential. Steps 1,2 and 3 simply add to this container, remove oxidizer in portions you are able to react at a time, maybe 3kg reactions at a time will be possible? Probably easier than 3 separate, time consuming 1kg reactions at 50 C.

5) Remove predetermined portion of MAA from storage container, and place in acid proof reaction vessel. This vessel must be fitted with some form of overhead mechanical stirring. It should at lest have a partiall sealed top, to help contain odours (and minimise evaporation of your toluene). A large excess of DRY TOLUENE is added. A large excess will be necessary if you are going to use mechanical stirring. This stirring mechanism would not be hard to make, easy from a power drill and an acid resistant rod. A fast spinning axle with a small impeller should be good for really whipping up the reaction mixture into a toluene/MAA milkshake. (The lower the temperature this reaction can be made to happen, then the better it probably will be).

6) Solvent (with large amount of dissolved benzaldehyde) is poured off. You may wish to add additional toluene to extract out as much of the benzaldehyde as possible. Use the mechanical mixer for each extraction.

7) Washing the solvent. Wash with water to remove excess acid. You may wish to back extract this water to reclaim some residual benzaldehyde/solvent. You could use a different solvent for the back extraction to conserve toluene. The water extracts could be fractionally distilled to recover some cell acid.

***This benzaldehyde laden solvent is the output from this process, it is put into a storage container and is removed when practical to do so, for the distillation process.***

8) MAS is transferred to solvent removal stage. This could be a vacuum vessel, or some kind of evaporator, or a solvent extraction using a low boiling solvent. Preferably low boiling as in < 50 C low boiling, maybe a higher pb could be used, uncertain at this time. A combination of (low boiling point) solvent extraction with subsequent vacuum evaporation could be used, or just plain old evaporation in a lowe humidity area, on a large acid resistant sheet could be used? Lots of possibilities.

9) MAS goes straight back into saturated MAA cell solution (from step 3) for regeneration, in 1 or more separate cells.

***Distillation process is run under vacuum. The first distillation could be run at normal pressure to drive off the toluene, then what remains is transferred to the vacuum distillation stage. Even a rather small vessel could do this, it would not have to be very big. I'm sure even a 250ml vessel could handle the output from this process, unless your regen cells were pumping out one heck of a current...No need for large vac. vessels***

Okay, I bet you're thinking this all sounds kinda complicated, well - it doens't have to be. Some of the steps can not only run at the same time, they can be combined.
For instance, 1 very large single cell could be run with a large hold up, say a few Kg solid material. Then, 1 Kg at a time can simply be removed when needed for the reaction, and the expended oxidizer from the last reaction (MAS) put back into the cell when convenient to do so.
Using that approach solves alot of practical issues, it just means that the cell will never be 100% regenerated at any given time - but who cares? Just keep an eye on the colour of the mix, keep it a dark-ish red, and make sure you keep organic solvent out of the regenerating mixture.
That large cell could also be the settling tank as well. Just switch it off for a while, it will settle pretty good in just a couple hours - if you are in a hurry. A scoop can retrieve the red paste or sludge from teh bottom, it's not difficult, believe me.
For a large single cell, some kind of overhead stirring would be a good idea -though I'm unclear how essential it would be (at this time).
Chunks of oxidizer that collect on the anode could either be A) broken off and mixed EVENLY with the solid material or B) maybe collected and used as the oxidizer. This would avoid the need to switch it off.

It is perhaps worth noting that this roto-batch style process - like most processes - has it's continual process equivalent, I think people oten refer to that as "going technical"
The continual process equivalent would use a MAA saturated solution of cell acid, that is pumped via the process equivalent of all the above steps/stages.
Only that instead of working with a solid mixture, you would be working with an acid solution (at some stages red, at others yellow), which is not without it's own set of challenges...ie. acid-resistant pipes, pumps, level regulators, flow controllers, etc. would need to be obtained.

Or the batch system could be miniaturised to produce benzaldehyde more regularly, only on a more manageable scale.

Doing EVERYTHING in single individual stages is alot of work.
Although the above proposal may have a solid material (MAA and MAS) holdup of perhaps 8 or 10Kg, running 10kg batches in single steps would be a nightmare, and very slow. It would be frustrating doing nothing, but waiting for your 10kg to regenerate.
If you were actually able to work with 10Kg batches, you would be thinking, hey I could be reacting another 10kg right now, and then extracting 10Kg, and then washing...
Maybe someone will actually do that, there's an idea?
10 sounds a lot better than 1.


[Edited on 10-2-2005 by CycloKnight]


[Edited on 29-8-2011 by MeSynth]

simba - 21-9-2011 at 08:51

Quote: Originally posted by questions  
Hey guys

I was told by someone that the cannizaro reaction only happens when the solution is alkalai and this is when the ph is 14 plus. I'm confused because i'm thinking about a reaction that happens between the ph range of 12 to 13 to make benzaldehyde from cinnamon aldehyde as previously disscussed
.
Thus does the cannizaro reaction only happen at a ph of at least 14 or can it even happen at a range of say between 12 and 13 with aldehydes?


This ain't true and if you had read the topic you would know that...there was a guy in this topic who did the reaction using sodium bicarbonate as base, so no way this was a ph 14.

cyphazard - 3-10-2011 at 22:08

I believe substituting the mno2 with mno4 would provide a better yield? I don't know that much chemistry however but its just an opinion. considering that its a liquid phase oxidation and that mno4 has more oxidization capability I think it could be of some use. the only negative "things" I can imagine going wrong is (1) a small scale side-reaction producing
mno2 and h20? which I dont think will really harm the yields at all and (2) the other being safety issues, but you already have knowledge concerning oxidizers so I dont think safety problems are an issue

=neat experiment, and nice thread

simba - 4-10-2011 at 14:11

Quote: Originally posted by cyphazard  
I believe substituting the mno2 with mno4 would provide a better yield? I don't know that much chemistry however but its just an opinion. considering that its a liquid phase oxidation and that mno4 has more oxidization capability I think it could be of some use. the only negative "things" I can imagine going wrong is (1) a small scale side-reaction producing
mno2 and h20? which I dont think will really harm the yields at all and (2) the other being safety issues, but you already have knowledge concerning oxidizers so I dont think safety problems are an issue

=neat experiment, and nice thread


You mean KMnO4?

KMnO4 will probably give a lot of benzoic acid instead. Just like oxidation of piperic acid to piperonal.

[Edited on 4-10-2011 by shivas]

Alastair - 24-10-2011 at 06:43

Could Na2SO3 be used in purification of benzaldehyde instead of NaHSO3? Is there a big difference?

simba - 27-10-2011 at 05:34

Quote: Originally posted by Alastair  
Could Na2SO3 be used in purification of benzaldehyde instead of NaHSO3? Is there a big difference?


Don't know about Na2SO3...but N2S2O5 can be used as a substitute.

peach - 10-12-2011 at 02:37

Reference


Remember, for some reason known only to the gods of Olympus, I no longer receive emails on reply. So you may be better PM'ing me if you've got any questions as I won't necessarily look at the threads for another 6 months or more; or I'll entirely forget I posted resuts to them.

Quote:
Ferrous-Copper Catalyst: Toluene (7.6 g.), water (35 ml.), ferrous sulphate (0.110 g.) heptahydrate, cupric acetate (0.072 g.) and methanol (8 ml.) are placed in a 250 ml. reactor.Sodium persulphate (47.05 g.) in an aqueous-methanol solution of sodium persulphate is added slowly to the mixture which is maintained at 70.degree. C., in an atmosphere of nitrogen and under agitation.The organic phase is separated after two hours and the aqueous phase is extracted with ethyl ether.The combined organic phases are distilled to afford 8.29 g. (95% yield) of very pure benzaldehyde (compared against a pure sample).


-Patent, Process for preparing aromatic aldehydes and ketones, Maggioni, March 27 1979, Filing number 4146582
Experimental


3.783g of toluene are added to a 100ml RBF. The salts were then added and the necks rinsed in with 4ml of methanol and 17.5ml of water. The central neck is stoppered and a gas tap is connected to each side neck. The flask is placed in the freezer at -30C.

Meanwhilst, 23.5g of sodium persulphate are weighed out and added to a separatory funnel. 50ml of water are added to this and it is vigorously shaken to solvate.

The flask is removed from the freezer and immediately placed in it's mantle, with a condenser now in the central neck and the stopper moved to the top of this. A vacuum is drawn through one side neck (remembering to also apply the vacuum to the argon line), it is shut off and argon allowed to enter through the other. The process is repeat 5 times before closing both taps with the flask at 1 atm of argon. Strong magnetic stirring is used throughout. Heat is applied gradually until a solid reflux from the condenser is seen. The mantles setting is noted.

Once reflux is obtained, the stopper is removed from the condenser and the drip tip of the funnel is inserted against a very gentle flow of argon. The persulfate solution is added as slowly as possible.

With the addition complete, the stopper was replaced in the condenser as the argon was switched off. The reaction was timed from the start of reflux and heating was removed after 2 hours. The entire setup was then removed from the mantle and placed in a small bath with a few ice cubes to cool.

The soon cooled contents of the flask were then emptied into a separatory funnel and 20 to 25ml of dichloromethane were added; shaking can be rather intense without a persistent emulsion, but the first separation will take time to settle well. This was decanted and stored, with 3ml of water being placed over the extract in storage. Four additional extractions were made with DCM at 5ml each, for a total of 40 to 45ml.

The aqueous layer was discarded and the funnel rinsed before returning the pooled organics. An additional 3ml of water was added (for 6ml in total) and vigorous, continuous shaking carried out for 5 minutes (timed). The funnel was left to separate for 6 minutes before recollecting the organic phase (in an aqueous rinsed flask) and discarding the aqueous. The drip tip of the funnel was dried with a length of tissue before returning the organic phase, to which 6ml of brine was then added. It is now acceptable to shake the funnel as hard as is physically possible and this was done for over three minutes. Two hours later, the organic phase was decanted to clean and acetone dried storage flask, blanketed with argon, stoppered and stored in the freezer at -30C.

The process was repeated again with 3.802g of toluene, verbatim bar that the flask was left to stand in cool water overnight prior to extraction, and that it only required 30ml of DCM to reach a colourless organic phase.

The two organic pools from these two runs were loaded into an all in one still with a short fractional column and head moulded into place. The glassware was repeatedly back purged with argon and then the dichloromethane removed at atmospheric pressure.

When the distillation ceased, the glassware was then placed under vacuum to remove any remaining traces of DCM, back purged with argon, put back under vacuum and the organic products were then distilled into a single flask, yielding an oily, colourless, aromatic liquid at room temperature.

The original mass of this flask was 44.96629g. It now weighs 49.76645g, giving a mass change of 4.80016g.

3.783g of toluene, plus another 3.802, gives a total substrate mass of 7.585g. The molar mass of toluene is 92.14 g/mol, and so 7.585g equates to 0.08232 moles. That of benzaldehyde is 106.12 g/mol, giving a complete conversion mass of 8.7g.

(4.8 / 8.7) x 100 = 55% from toluene

Errors and oddities


The flask is not an ideal size, it ends up with about 80ml in a 100ml, but it didn't cause any problems.

Most references use ether for extracting benzaldehyde, as they both float on the aqueous layer. I don't have any (supplier lost the order and then ran out of it), so I went with dichloromethane, not wanting to start with toluene and knowing the cyclohexane I have needs redistilling anyway (it's still purple from messing around extracting seaweed). Dichloromethane is denser than the aqueous and organic layer in the separation. So it needs considerably more than it would with less dense solvents to flip the organic layer down to the base of the funnel. One useful thing is that having it at the bottom makes for easier subsequent extractions of the aqueous layer (it can stay in the funnel and simply have some more DCM poured in). It also keeps it away from the atmosphere to some extent, since it's sat down at the base under the water, but doubt it's all that much of an issue.

I didn't have enough bisulphite to form the adduct from the results. And, my fancy snazzy ground thermometer had died, so I can't fractionally distill until the new ones turn up. As a result, I had to distill the results and apply some logic to estimate what was going on.

Someone else, in some other thread perhaps, suggested that a slight excess of oxidiser would be a good idea when oxidising benzyl alcohol or toluene to the aldehyde, as the result should be that all of the alcohol is converted to the aldehyde, tars or a small amount of benzoic acid.

Have a look at these melting and boiling points (they're all in Celsius and ordered from lowest BP up);

Toluene
MP -93
BP 110.6

Benzyl Alcohol
MP -15
BP 205

Benzaldehyde
MP -26
BP 178.1

Benzoic Acid
MP 122.38
BP 250

The boiling points sweep up, but the melting points do not. Indeed, the first three are all liquids below 0C, whereas the benzoic acid is a solid over 100C. It will solidify in a cold condenser.

After collecting the lower boiling materials and reaching a point where I could no longer remove anything from the glass, I stopped. On allowing the glass to cool, I discovered the remaining liquid rapidly solidified. Furthermore, and much to my enjoyment, it stopped within literally 10mm or so of leaving the still head, with the last drip on the way out remaining a liquid. And suggesting the benzoic has been largely left behind in the still.

Making the assumption that all of the lower BP's have been converted to tar, benzaldehyde or benzoic acid, the liquid collected should be mainly benzaldehyde.

This is certainly a leap of faith to make, and I doubt it is perfectly true, but I suspect it is reasonably so.

Yield seems kind of low there


It does.

I have followed the patent rather closely, even using vacuums and argon for the atmosphere as opposed to only blowing a stream of nitrogen in.

The only two differences that come to mind are that I used DCM rather than ether.

The copper acetate I generated months and months ago when I was playing around with jam jars and the new power supply in the kitchen. It was produced using acetic (not vinegar) in water with cleaned copper wire from a bit of Twin and Earth. So that should be rather clean indeed.









The iron sulphate came from some nails. I first gave them a boil in sulphuric to scrub their surfaces, then emptied it all out, gave it all a rinse, put them back in with some water and a corresponding amount of sulphuric and warmed them overnight. The next day, I ran that through a ?1?um filter paper to get any solid out and received a very faint (barely visible), soft, greeny blue solution. Overtime, I noticed some form of sediment appearing in this, perhaps an iron oxide. I have possibly made a mistake here and the iron is not functioning as it should be in the oxidation.

It is also possible my persulphate is not truly all persulphate, that might be worth investigating.

At least it demonstrates the oxidation with persulphate does function anyway. Someone else (magpie / len / woelen / another?) has gotten a yield over 50% from persulphate also, using water alone (no salts, no methanol).

I have also tried it from benzyl alcohol, which also works. Although it seemed easier to oxidise it all to tar.

The solution does indeed need to be at 70C before the reaction starts, and the oxidiser should only go in slowly, in solution, when it does. As adding it only partially dissolved seems to encourage tars. As does running the reaction vastly above 70C. I have tried it with neat benzyl alcohol and the result was nothing less than a total mess! Both phases in the flask were dark brown within minutes, despite being under argon.

I believe the original patent suggests the specific values it does for water and methanol in the flask for good reason. The methanol not only helps fix the BP towards 70C, but combines the toluene / benzyl alcohol phase with the water, allowing the oxidiser access to more substrate and better dilution as opposed to coming into point contact with smaller amounts; where upon it forms tars (e.g. my neat benzyl alcohol test, which was also a lot hotter than 70C).

The gallery.


<a href="http://img9.imageshack.us/i/img1697zz.jpg/" target="_blank"><img src="http://img9.imageshack.us/img9/3875/img1697zz.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img193.imageshack.us/i/img1698x.jpg/" target="_blank"><img src="http://img193.imageshack.us/img193/1921/img1698x.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img52.imageshack.us/i/img1701vs.jpg/" target="_blank"><img src="http://img52.imageshack.us/img52/1276/img1701vs.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img708.imageshack.us/i/img1702nd.jpg/" target="_blank"><img src="http://img708.imageshack.us/img708/8987/img1702nd.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img21.imageshack.us/i/img1703m.jpg/" target="_blank"><img src="http://img21.imageshack.us/img21/8939/img1703m.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img215.imageshack.us/i/img1704ek.jpg/" target="_blank"><img src="http://img215.imageshack.us/img215/9492/img1704ek.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img585.imageshack.us/i/img1705e.jpg/" target="_blank"><img src="http://img585.imageshack.us/img585/8250/img1705e.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img28.imageshack.us/i/img1706xt.jpg/" target="_blank"><img src="http://img28.imageshack.us/img28/9030/img1706xt.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img823.imageshack.us/i/img1707i.jpg/" target="_blank"><img src="http://img823.imageshack.us/img823/2682/img1707i.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img220.imageshack.us/i/img1708v.jpg/" target="_blank"><img src="http://img220.imageshack.us/img220/8799/img1708v.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img97.imageshack.us/i/img1709k.jpg/" target="_blank"><img src="http://img97.imageshack.us/img97/9651/img1709k.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img805.imageshack.us/i/img1710m.jpg/" target="_blank"><img src="http://img805.imageshack.us/img805/9366/img1710m.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img4.imageshack.us/i/img1711kw.jpg/" target="_blank"><img src="http://img4.imageshack.us/img4/9751/img1711kw.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img696.imageshack.us/i/img1712mg.jpg/" target="_blank"><img src="http://img696.imageshack.us/img696/4857/img1712mg.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img171.imageshack.us/i/img1713fu.jpg/" target="_blank"><img src="http://img171.imageshack.us/img171/4080/img1713fu.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img17.imageshack.us/i/img1715n.jpg/" target="_blank"><img src="http://img17.imageshack.us/img17/7352/img1715n.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img202.imageshack.us/i/img1716au.jpg/" target="_blank"><img src="http://img202.imageshack.us/img202/1655/img1716au.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img248.imageshack.us/i/img1717o.jpg/" target="_blank"><img src="http://img248.imageshack.us/img248/2225/img1717o.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img405.imageshack.us/i/img1718ae.jpg/" target="_blank"><img src="http://img405.imageshack.us/img405/2905/img1718ae.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img835.imageshack.us/i/img1719l.jpg/" target="_blank"><img src="http://img835.imageshack.us/img835/34/img1719l.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img823.imageshack.us/i/img1720be.jpg/" target="_blank"><img src="http://img823.imageshack.us/img823/5271/img1720be.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img36.imageshack.us/i/img1721so.jpg/" target="_blank"><img src="http://img36.imageshack.us/img36/39/img1721so.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img16.imageshack.us/i/img1723dl.jpg/" target="_blank"><img src="http://img16.imageshack.us/img16/6893/img1723dl.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img17.imageshack.us/i/img1724h.jpg/" target="_blank"><img src="http://img17.imageshack.us/img17/3707/img1724h.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img841.imageshack.us/i/img1727cj.jpg/" target="_blank"><img src="http://img841.imageshack.us/img841/5496/img1727cj.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img829.imageshack.us/i/img1729dw.jpg/" target="_blank"><img src="http://img829.imageshack.us/img829/2600/img1729dw.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img585.imageshack.us/i/img1730by.jpg/" target="_blank"><img src="http://img585.imageshack.us/img585/7420/img1730by.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img26.imageshack.us/i/img1731sm.jpg/" target="_blank"><img src="http://img26.imageshack.us/img26/1027/img1731sm.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img703.imageshack.us/i/img1732qx.jpg/" target="_blank"><img src="http://img703.imageshack.us/img703/691/img1732qx.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img208.imageshack.us/i/img1734a.jpg/" target="_blank"><img src="http://img208.imageshack.us/img208/4383/img1734a.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img855.imageshack.us/i/img1738g.jpg/" target="_blank"><img src="http://img855.imageshack.us/img855/2659/img1738g.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img402.imageshack.us/i/img1739kx.jpg/" target="_blank"><img src="http://img402.imageshack.us/img402/9683/img1739kx.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img818.imageshack.us/i/img1740c.jpg/" target="_blank"><img src="http://img818.imageshack.us/img818/5711/img1740c.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img43.imageshack.us/i/img1741p.jpg/" target="_blank"><img src="http://img43.imageshack.us/img43/6635/img1741p.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img32.imageshack.us/i/img1742c.jpg/" target="_blank"><img src="http://img32.imageshack.us/img32/4615/img1742c.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img248.imageshack.us/i/img1744g.jpg/" target="_blank"><img src="http://img248.imageshack.us/img248/9084/img1744g.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img84.imageshack.us/i/img1747py.jpg/" target="_blank"><img src="http://img84.imageshack.us/img84/1396/img1747py.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img820.imageshack.us/i/img1749l.jpg/" target="_blank"><img src="http://img820.imageshack.us/img820/5711/img1749l.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img443.imageshack.us/i/img1768liju.jpg/" target="_blank"><img src="http://img443.imageshack.us/img443/3063/img1768liju.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img39.imageshack.us/i/img1769d.jpg/" target="_blank"><img src="http://img39.imageshack.us/img39/9869/img1769d.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img259.imageshack.us/i/img1774cb.jpg/" target="_blank"><img src="http://img259.imageshack.us/img259/9189/img1774cb.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img202.imageshack.us/i/img1776fe.jpg/" target="_blank"><img src="http://img202.imageshack.us/img202/4659/img1776fe.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img809.imageshack.us/i/img1777r.jpg/" target="_blank"><img src="http://img809.imageshack.us/img809/1371/img1777r.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img811.imageshack.us/i/img1779bo.jpg/" target="_blank"><img src="http://img811.imageshack.us/img811/1166/img1779bo.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img585.imageshack.us/i/img1780c.jpg/" target="_blank"><img src="http://img585.imageshack.us/img585/6427/img1780c.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img24.imageshack.us/i/img1782yi.jpg/" target="_blank"><img src="http://img24.imageshack.us/img24/2718/img1782yi.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img855.imageshack.us/i/img1783x.jpg/" target="_blank"><img src="http://img855.imageshack.us/img855/2996/img1783x.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img195.imageshack.us/i/img1784xm.jpg/" target="_blank"><img src="http://img195.imageshack.us/img195/3538/img1784xm.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img836.imageshack.us/i/img1785z.jpg/" target="_blank"><img src="http://img836.imageshack.us/img836/7245/img1785z.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img3.imageshack.us/i/img1787my.jpg/" target="_blank"><img src="http://img3.imageshack.us/img3/4816/img1787my.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img822.imageshack.us/i/img1788ap.jpg/" target="_blank"><img src="http://img822.imageshack.us/img822/4710/img1788ap.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img46.imageshack.us/i/img1790l.jpg/" target="_blank"><img src="http://img46.imageshack.us/img46/8968/img1790l.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img52.imageshack.us/i/img1793nm.jpg/" target="_blank"><img src="http://img52.imageshack.us/img52/2531/img1793nm.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img192.imageshack.us/i/img1794j.jpg/" target="_blank"><img src="http://img192.imageshack.us/img192/564/img1794j.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img839.imageshack.us/i/img1796c.jpg/" target="_blank"><img src="http://img839.imageshack.us/img839/2148/img1796c.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img163.imageshack.us/i/img1800wh.jpg/" target="_blank"><img src="http://img163.imageshack.us/img163/9251/img1800wh.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a>

[Edited on 10-12-2011 by peach]

peach - 10-12-2011 at 04:12

I ran the cell as well, months ago. And whilst my thermometer was still functional; so I could be sure of what was coming out in a fractional column distillation.

I originally uploaded these to facebook, and then had to format my computer. Which meant downloading them all again. Facebook wrecked the file numbering, so then they needed downloading again to keep them in sequence. Then the upload tool decided the next file after 1 should be 10, 11, 12 etc. More file renaming... very tedious. With the notes missing in action due to the format, all I can do is comment on what I remember.

What I remember, is that this thing is stupidly huge for the substrate mass!

In some of the photos, I've switched the stirring off so you can see the layers. To restart the stirring would mean reaching in there with a glass rod and jabbing at the stir bar to get it free from the silt. I recall this yielding around 50% as well (although that is really pushing into the vague memories there). It was run as per the description (I can't find the reference patent now), but didn't go quite as to plan.

Generating the bioxide was fine! But running the substrate through was odd.

I would add the toluene, hold the cell temperature and wander off. As I'd transferred it from a nearly full 800ml beaker to a 3l beaker, I could stir it extremely hard. After the allotted time, I would come back and pipette off the top layer, and give it another extraction with toluene or cyclohexane (I think cycloknight asked at one point, how to remove the toluene such that it didn't interfering with other substrates or gradually contaminate the cell). They steam distill it in the patent, but then you need to keep track of the moisture content instead.

On the first attempt, I did not receive back the expected amount of aldehyde. More interestingly, the cell had barely changed colour. So I added some more toluene and ran it again for the set amount of time. Again, still not the complete amount and still the cell remained the incorrect colour.

A third time round, I was wondering what was going on! But returned and bingo, the cell had gone right back to a banana milkshake yellow and the yield of aldehyde was starting to make a bit more sense.

The initial thought would be, all the rest of the yield had evaporated off as toluene, before oxidation. But I was also getting toluene in the results. And not vast amounts of tar or higher oxidation products.

I am still not entirely sure what happened there, but can only think of running this in a flask with a condenser on it, to ensure the amount of toluene going in, stays well contained, and to perhaps use some excess to ensure there's enough there, well mixed with the aqueous phase, for it to complete in one go. I didn't want to run it in a flask initially as oval bars aren't as good as the flat ones for stirring, and I don't have a 2l sized mantle that'll stir at the same time, or an overhead stirrer. It was also easier to make the electrodes for a beaker and I would be less bothered about damaging the beakers than a 2l, 3 neck flask.

The cell is fun to do, it's not specific to toluene and it yields reasonably, but boy o' boy is it a monster!

I dumped the cell it's self back out and into a HDPE bottle at the end, so I can always reuse it at some later date for something else; quite easily (only needs regenerating).

I would have put a photo up of the cell at the end of the process, banana yellow, but that went with the format.

Photo gallery.


This sheet of lead actually spent it's life as the bend at the back of a toilet. I cut a slit in it, spread it out flat, then proceeded with some heavy duty wire brush in a hand drill cleaning. After that it got a wash with some acid and then another clean with the wire brush. Sparkly. MeMe the cat is getting in on this photo.
<a href="http://img11.imageshack.us/i/11654117.jpg/" target="_blank"><img src="http://img11.imageshack.us/img11/5682/11654117.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img705.imageshack.us/i/67163112.jpg/" target="_blank"><img src="http://img705.imageshack.us/img705/6307/67163112.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img638.imageshack.us/i/89346130.jpg/" target="_blank"><img src="http://img638.imageshack.us/img638/8317/89346130.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img831.imageshack.us/i/18822703.jpg/" target="_blank"><img src="http://img831.imageshack.us/img831/7334/18822703.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img842.imageshack.us/i/16659175.jpg/" target="_blank"><img src="http://img842.imageshack.us/img842/2411/16659175.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img526.imageshack.us/i/29597804.jpg/" target="_blank"><img src="http://img526.imageshack.us/img526/3648/29597804.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img3.imageshack.us/i/59695638.jpg/" target="_blank"><img src="http://img3.imageshack.us/img3/9376/59695638.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>

I'll hang onto that and maybe have a go at some lead salts with it. Lead cuts like hard cheese when using a hand saw, it's a sumptuous feeling. After cutting them, I ran a file over the edges to make them pretty. I put the sheets back in the beaker with the stir bar and bumped them off the top of the bar, so as to determine how high they'd need to be to ensure the the bar wouldn't start banging into them overnight.

I then bent a lip on them, hammered the lip flat and bent them around a large can of tinned fruit, approximately the same size as the beaker it's self.
<a href="http://img9.imageshack.us/i/74783092.jpg/" target="_blank"><img src="http://img9.imageshack.us/img9/6858/74783092.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img546.imageshack.us/i/33739733.jpg/" target="_blank"><img src="http://img546.imageshack.us/img546/9285/33739733.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img217.imageshack.us/i/26273988.jpg/" target="_blank"><img src="http://img217.imageshack.us/img217/7559/26273988.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img403.imageshack.us/i/17146561.jpg/" target="_blank"><img src="http://img403.imageshack.us/img403/8476/17146561.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img684.imageshack.us/i/14582506.jpg/" target="_blank"><img src="http://img684.imageshack.us/img684/4803/14582506.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img268.imageshack.us/i/49910689.jpg/" target="_blank"><img src="http://img268.imageshack.us/img268/2098/49910689.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img193.imageshack.us/i/98587012.jpg/" target="_blank"><img src="http://img193.imageshack.us/img193/6715/98587012.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img46.imageshack.us/i/26079353.jpg/" target="_blank"><img src="http://img46.imageshack.us/img46/8223/26079353.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img502.imageshack.us/i/69745185.jpg/" target="_blank"><img src="http://img502.imageshack.us/img502/5855/69745185.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img195.imageshack.us/i/94991006.jpg/" target="_blank"><img src="http://img195.imageshack.us/img195/730/94991006.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img43.imageshack.us/i/52124499.jpg/" target="_blank"><img src="http://img43.imageshack.us/img43/1930/52124499.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img6.imageshack.us/i/14595331.jpg/" target="_blank"><img src="http://img6.imageshack.us/img6/9818/14595331.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>

Need to be careful with these things involving electricity that you don't use wire that is going to melt in the middle of the night and torch the house. My cell pulled 5 amps at it's maximum. This cable can easily manage 5 amps (it's 13 amp mains flex). I also soldered the leads to the electrodes so they wouldn't be constantly making and breaking, or giving weird voltage / current readings.
<a href="http://img707.imageshack.us/i/12891398.jpg/" target="_blank"><img src="http://img707.imageshack.us/img707/5924/12891398.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img818.imageshack.us/i/18375984.jpg/" target="_blank"><img src="http://img818.imageshack.us/img818/4927/18375984.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img600.imageshack.us/i/18323660.jpg/" target="_blank"><img src="http://img600.imageshack.us/img600/9946/18323660.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img687.imageshack.us/i/25713253.jpg/" target="_blank"><img src="http://img687.imageshack.us/img687/2747/25713253.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img844.imageshack.us/i/70674566.jpg/" target="_blank"><img src="http://img844.imageshack.us/img844/7143/70674566.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>

I'm not using fancy clean acid when it needs so much of it. That's drain stuff. It's concentrated, but clearly mucky due to contact with some organic at some point in the bottling. To make the colours more true to themselves, rather than contamination, I got the acid nice and toasty warm and began adding 35% peroxide to destroy the carbonaceous stuff. Careful.
<a href="http://img214.imageshack.us/i/28525988.jpg/" target="_blank"><img src="http://img214.imageshack.us/img214/9361/28525988.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>

It took a while to go, but you can see it's fizzing out of existence.
<a href="http://img32.imageshack.us/i/12346873.jpg/" target="_blank"><img src="http://img32.imageshack.us/img32/3664/12346873.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>

Meanwhilst... weighing out the equally monstrous quantities of salt.
<a href="http://img442.imageshack.us/i/79144631.jpg/" target="_blank"><img src="http://img442.imageshack.us/img442/791/79144631.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img408.imageshack.us/i/40108666.jpg/" target="_blank"><img src="http://img408.imageshack.us/img408/5545/40108666.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img853.imageshack.us/i/27604024.jpg/" target="_blank"><img src="http://img853.imageshack.us/img853/2843/27604024.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>

Acid's looking much better. Needs to be diluted down. Water content is an issue the patent mentions.
<a href="http://img812.imageshack.us/i/85825377.jpg/" target="_blank"><img src="http://img812.imageshack.us/img812/6733/85825377.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>

Water into scalding hot concentrated acid right? :D Nah... not right, so again, do be careful if you repeat the process. I am dripping it in, slowly, with cling film (saran wrap) over the top to keep any spitting inside the beaker.
<a href="http://img405.imageshack.us/i/77378246.jpg/" target="_blank"><img src="http://img405.imageshack.us/img405/4833/77378246.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img408.imageshack.us/i/24757348.jpg/" target="_blank"><img src="http://img408.imageshack.us/img408/7165/24757348.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img859.imageshack.us/i/47850366.jpg/" target="_blank"><img src="http://img859.imageshack.us/img859/7016/47850366.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img404.imageshack.us/i/93638944.jpg/" target="_blank"><img src="http://img404.imageshack.us/img404/1411/93638944.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>

Salts are in, Nesquick pink milkshake achieved. Probably a little on the tangy side.
<a href="http://img707.imageshack.us/i/93745386.jpg/" target="_blank"><img src="http://img707.imageshack.us/img707/17/93745386.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img94.imageshack.us/i/24729570.jpg/" target="_blank"><img src="http://img94.imageshack.us/img94/355/24729570.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>

Ready?
<a href="http://img141.imageshack.us/i/71959568.jpg/" target="_blank"><img src="http://img141.imageshack.us/img141/9280/71959568.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>

The juice is loose.
<a href="http://img408.imageshack.us/i/53253874.jpg/" target="_blank"><img src="http://img408.imageshack.us/img408/4655/53253874.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>

Ten minutes later. Again, I found I had to cling film the top of this. Right from the start, even though it's not all that warm, the little bubbles popping around the electrodes were flicking spots of acid around.
<a href="http://img217.imageshack.us/i/99366584.jpg/" target="_blank"><img src="http://img217.imageshack.us/img217/3994/99366584.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img807.imageshack.us/i/17012738.jpg/" target="_blank"><img src="http://img807.imageshack.us/img807/1114/17012738.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img196.imageshack.us/i/45857876.jpg/" target="_blank"><img src="http://img196.imageshack.us/img196/4120/45857876.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img710.imageshack.us/i/31638385.jpg/" target="_blank"><img src="http://img710.imageshack.us/img710/8025/31638385.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img233.imageshack.us/i/31126857.jpg/" target="_blank"><img src="http://img233.imageshack.us/img233/9203/31126857.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>

I think I calculated it'd take about 10 hours at the original current, can't remember. But I did start drawing a graph of the voltage against the current, with the temperature and a predicted end point. I then averaged the line as I was moving along to work out how much current had gone through.

The blue line is voltage, the red is current and the gray pencil line is temperature.

Notice the maximums on the supply a few photos up. I could not get anymore through it than it shown on the graph. I might have a look into making porous lead electrodes, if only for the fun of trying; does anyone have an information on how it's produced? The supply may not be a super nice Lambda one, but I am confident it can manage more than the 25 or so watts going through there (as I've seen it do so).
<a href="http://img818.imageshack.us/i/81928436.jpg/" target="_blank"><img src="http://img818.imageshack.us/img818/4012/81928436.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img59.imageshack.us/i/54618516.jpg/" target="_blank"><img src="http://img59.imageshack.us/img59/6529/54618516.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img403.imageshack.us/i/18157313.jpg/" target="_blank"><img src="http://img403.imageshack.us/img403/4109/18157313.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img820.imageshack.us/i/83416294.jpg/" target="_blank"><img src="http://img820.imageshack.us/img820/6028/83416294.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img88.imageshack.us/i/29720446.jpg/" target="_blank"><img src="http://img88.imageshack.us/img88/3346/29720446.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img690.imageshack.us/i/85523649.jpg/" target="_blank"><img src="http://img690.imageshack.us/img690/7893/85523649.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img705.imageshack.us/i/86515697.jpg/" target="_blank"><img src="http://img705.imageshack.us/img705/6656/86515697.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>

The temperature was held at a continual 50C throughout the toluene's visit.
<a href="http://img191.imageshack.us/i/86652182.jpg/" target="_blank"><img src="http://img191.imageshack.us/img191/7646/86652182.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img341.imageshack.us/i/31486354.jpg/" target="_blank"><img src="http://img341.imageshack.us/img341/9172/31486354.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img690.imageshack.us/i/66872450.jpg/" target="_blank"><img src="http://img690.imageshack.us/img690/4430/66872450.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img12.imageshack.us/i/71527180.jpg/" target="_blank"><img src="http://img12.imageshack.us/img12/9435/71527180.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img525.imageshack.us/i/59662522.jpg/" target="_blank"><img src="http://img525.imageshack.us/img525/291/59662522.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img408.imageshack.us/i/16315995.jpg/" target="_blank"><img src="http://img408.imageshack.us/img408/6844/16315995.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img35.imageshack.us/i/32261400.jpg/" target="_blank"><img src="http://img35.imageshack.us/img35/1296/32261400.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img684.imageshack.us/i/87625467.jpg/" target="_blank"><img src="http://img684.imageshack.us/img684/4492/87625467.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img818.imageshack.us/i/30749177.jpg/" target="_blank"><img src="http://img818.imageshack.us/img818/1764/30749177.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img13.imageshack.us/i/58772392.jpg/" target="_blank"><img src="http://img13.imageshack.us/img13/2051/58772392.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img560.imageshack.us/i/93187739.jpg/" target="_blank"><img src="http://img560.imageshack.us/img560/3185/93187739.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img256.imageshack.us/i/39717404.jpg/" target="_blank"><img src="http://img256.imageshack.us/img256/2217/39717404.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img403.imageshack.us/i/58934023.jpg/" target="_blank"><img src="http://img403.imageshack.us/img403/8131/58934023.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img819.imageshack.us/i/22338971.jpg/" target="_blank"><img src="http://img819.imageshack.us/img819/156/22338971.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img64.imageshack.us/i/30243367.jpg/" target="_blank"><img src="http://img64.imageshack.us/img64/2328/30243367.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img267.imageshack.us/i/74658275.jpg/" target="_blank"><img src="http://img267.imageshack.us/img267/5069/74658275.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img607.imageshack.us/i/87339060.jpg/" target="_blank"><img src="http://img607.imageshack.us/img607/8908/87339060.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img412.imageshack.us/i/22667934.jpg/" target="_blank"><img src="http://img412.imageshack.us/img412/1262/22667934.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a><br>
<a href="http://img210.imageshack.us/i/18382615.jpg/" target="_blank"><img src="http://img210.imageshack.us/img210/828/18382615.jpg" alt="Free Image Hosting at www.ImageShack.us" border="0"/></a>

Oooooo!

15kW, programmable. :D

Dear Santa...



[Edited on 10-12-2011 by peach]

Paddywhacker - 15-12-2011 at 20:37

Thanks for that Peach. The photographs were excellent. For completeness would you please cut & paste the amounts and times from the earlier post so that it is all in one place. It would make a nice PDF.

Sedit - 23-12-2011 at 21:23

Quote:
It was run as per the description (I can't find the reference patent now), but didn't go quite as to plan.


You made the same mistake myself and everyone else has so far, you just tossed in the Toluene and stirred when the patents say to add the oxidizer to warmed toluene drip wise. I honestly feel this will make a huge difference. Huge enough that I am going to set back up a similar cell that generates Mn(IV) oxidizer because I have faith that this minor change will greatly affect the yield.

peach - 24-12-2011 at 00:06

Quote: Originally posted by Sedit  
Quote:
It was run as per the description (I can't find the reference patent now), but didn't go quite as to plan.


You made the same mistake myself and everyone else has so far.


The cell and manganese oxidiser come from US patent 808095.

Quote:
After the water evaporated during electrolysis has been replaced, the entire electrolyzing mixture is stirred together with four kilos of toluene in a closed lead-coated receptacle provided with a stirrer. The temperature is maintained at 50 degrees centrigrade.


No mention of dripping it in there. Besides, the electrolyzing mixture of which he speaks is packed so full of solid it takes effort to stir it, let alone drip it. The results also tend to be under oxidised as opposed to over, even when the substrate is simply poured in and left to stir at 50 degrees Celsius for hours. I actually fell asleep on the second go through and left it going for some ridiculous amount of time, returning to find it still hadn't gone to completion and needed more toluene.

The cell seems to benefit from using an excess of toluene and churning it as hard as possible to get the two into contact. Mine was stirring hard enough I could see the bottom of the beaker and the organic layer disappeared until the stirring was switched off and the contents allowed to settle. Harder than that.

You may be thinking of US 4146582.

Quote:
The temperature of the rection mixture is raised to 80°C and a flow of nitrogen is fed to the reactor under fierce agitation while drip feeding a solution of sodium persulfate (103.4g of Na2S2O8 in 335ml of H2O).


In which case, I did drip the oxidiser in and with the solution at that temperature, being stirred and under argon.

There are only two possible faults with my version of the persulphate method.

I used DCM as opposed to ether to extract the result.

More importantly, I could see cloudiness in the filtrate of the iron sulphate I was using, suggesting one of the catalysts may not have been in such great condition.

I have some supplier benzaldehyde spare if you guys ever tire of running cells etc. Personally, I have two other entirely none benzaldehyde related things I want to get on with this week and next, so it may be a wHile before I retry the persulphate oxidation. I've got a feeling I may do, as it is already nagging at me that something has gone a little too far amiss on the yield versus his claim. One of said things is making a decent amount of ether (as the supplier lost my bottle of it and then ran out of it), which would also solve one of those two questions. Although, I seriously doubt it was swapping ether for DCM that caused the change in yield, and suspect the iron sulphate.

PM me if you want some minus this twenty page thread of effort.

Quote:
He doesnt state how many seconds that were between each drip of cinnamon as it dripped into the 2L boiling solution of water and NaOH and he doesnt state how long it took for the product to be completely distilled.

If I was to use the same amount of cinnamon oil that cyclonight used but instead of using 2L of boiling solution of water and NaOH like he used, say I used an 8L of solution instead, does that mean I would need four times as much steam pressure to get the same amount of product to disstill over?


Set the drip rate so it corresponds, roughly, to the rate at which it's appearing in the receiver. Failing that, just go as slowly as the funnel will allow.

Pressure wise, no, it's the same pressure. The only changes you'd make would be with regards to the amount of cinnamaldehyde used. The more of it that goes in, the more steam volume needed and the longer it takes for it to all go across to the receiver. Also, as he and the patent applicant note, the pH of the solution can fall too low as the reaction occurs. Using more feedstock, you'd likely have to add some more base as it went along.

The glassware is not pressurised by the steam in cycloknights example. It will be passing through at approximately 1 atmosphere of pressure. Four times that would be about 60 psi. In a glass flask, that will likely cause the flask to burst as most glassware is tentatively rated for 10 or 15 psi max.

[Edited on 24-12-2011 by peach]

Nicodem - 25-12-2011 at 03:17

I cleaned up the last two pages of the thread by splitting of the off topic beginner discussion on the cinnamaldehyde retro-aldol reaction that questions enforced for the last couple of months. The posts are now in the new thread he created for this purpose: https://www.sciencemadness.org/whisper/viewthread.php?tid=18...

I hope this thread will stay clear of any such fruitless off topic discussion from now on.

questions - 25-12-2011 at 03:42

sorry guys

questions - 25-12-2011 at 03:51

Hye I clicked on the link and it doesnt take me to the thread...... whats going on?

questions - 1-1-2012 at 22:21

Theres all this talk and excitement around liquid phase oxidation of toluene to benzaldehyde.

Has anyone tried the oxidation of toluene to benzaldehdye using the vapour vase method where titanium catylist is used?

questions - 2-1-2012 at 11:55

Here's a good site for making benzaldehyde from toluene by oxidising the toluene in the presence of sulfuric acid and manganese dioxide.

http://www.faizkaskar.8k.com/processelection.html

questions - 3-1-2012 at 23:26

You know, when I think of it, I realise that the toluene oxidation method realy isnt so bad.

To be honest with you, theres really two things about it that I dont like:

1) it's very time consuming and difficult to keep the cell clean of benz and tol and byproducts afterusing it the first time.

2) I hate doing vacuum disstilations and having to use scientific glassware.

So here is a sugestion that I think is worth you trying. In stead of vacuum disstilling the benzaldehyde out, just shake it with a solution of sodium bisulfite and the benzaldehyde will precipitate. Then add NaOH or ever bicarb powder to break up the aduct and this will result in pure benzaldehyde. It's quick, easy and doesnt require all that bullshit disstillation stuffing around and equipment.

Has anyone actualy tried using the sodium bisulfite method to precipitate the benzaldehyde out of the toluene when usig the electric cell to make benzaldehyde?

questions - 3-1-2012 at 23:33

Quote: Originally posted by Sedit  
Quote:
It was run as per the description (I can't find the reference patent now), but didn't go quite as to plan.


You made the same mistake myself and everyone else has so far, you just tossed in the Toluene and stirred when the patents say to add the oxidizer to warmed toluene drip wise. I honestly feel this will make a huge difference. Huge enough that I am going to set back up a similar cell that generates Mn(IV) oxidizer because I have faith that this minor change will greatly affect the yield.


How has this experiment been going?

Sedit - 3-1-2012 at 23:34

Have you even tried this method by any chance? It should be steam distilled out nothing more. Everything else is a pain in the dick including solvent extraction.

questions - 4-1-2012 at 00:43

Quote: Originally posted by Sedit  
Have you even tried this method by any chance? It should be steam distilled out nothing more. Everything else is a pain in the dick including solvent extraction.


As a matter of fact I have tried this method, I was using this method for like six straight months. I was boiling out the toluene at 115C to 120C and then I was vacuum disstiling out the benzaldehyde at around 90C. I hated the whole procedure because I wouldnt get anymore than 75ml :(

It sucked arse

Sedit - 4-1-2012 at 00:58

Have you attempted steam distillation to avoid the messy workup by any chance?

I aways put a mark on the flask where the oxidant level was before steam distilling incase I lose some fluid altering the concentration along the way. Start heating the flask and once its up to temperature pass steam into it and collect the vapors.

questions - 4-1-2012 at 05:55

Quote: Originally posted by Sedit  
Have you attempted steam distillation to avoid the messy workup by any chance?

I aways put a mark on the flask where the oxidant level was before steam distilling incase I lose some fluid altering the concentration along the way. Start heating the flask and once its up to temperature pass steam into it and collect the vapors.


I never needed to do a steam distilation because the vacuum disstilation worked perfectly. I just hated having to work with all the delicate and expensive and elusive glassware.

questions - 4-1-2012 at 05:57

Quote: Originally posted by Sedit  
Have you attempted steam distillation to avoid the messy workup by any chance?

I aways put a mark on the flask where the oxidant level was before steam distilling incase I lose some fluid altering the concentration along the way. Start heating the flask and once its up to temperature pass steam into it and collect the vapors.


Theoritically it should be easier and quicker to just use sodium bisulfite to precipitate it out and then just add bicard to it to convert it back to an liquid.

Sedit - 4-1-2012 at 19:31

No because you are steam distilling it directly out of the oxidant without the need of excess Toluene to extract it.

questions - 5-1-2012 at 04:49

Quote: Originally posted by Sedit  
No because you are steam distilling it directly out of the oxidant without the need of excess Toluene to extract it.


So you mean to say that after the toluene i the cell had converted to benzaldehyde, you blow steam through the whole discharged cell to lift ou the formed benzaldehyde with them steam where it is cndensed with the steam?

Sedit - 5-1-2012 at 13:04

Yes.

questions - 6-1-2012 at 07:51

I love benzaldehyde, not just for it's broad uses, but because of it's signature smell and oily texture, it's also very expensive in australia as well I hear.

I've been doing a lot of research into the reaction of cinnamon aldehyde in a boiling solution of water with ph 11 to 13 and antifoaming agent. I know this thread is all about toluene but I'm posting it here because more people ot at this thread, also cyclonight made many posts and no one knocked him for doing so.

Anyway, I've tried the experiment and have found that the more benzaldehyde is made, the more tar is formed in the reaction.
After an 7 hour reaction of 200ml of cinnamon aldehyde in a 2L solution of boling water with a steady ph of 12.5 and antifoaming agent, only 30% was benzaldehyde, 20% was unreacted cinnamon and the other 50% was all this tar shit.

I think that the aceteldehyde is reacting with the benzaldehyde in this base solution and that is what is making all this tar shit. Because I don't believe that this tar shit is a product of the cinnamon turning into benzaldehyde and acetaldehyde, I think that shortly after the benzaldehyde has formed, it reacts with the acetaldehyde that has formed. I cant think of any other explanation and I certainly dont think that the benzaldehyde is reacting with the cinnamon, could it????

If it is such that the formed benzaldehyde is reacting with the formed acetaldehyde, what can we put in place to stop or even minimise this from happening?

questions - 6-1-2012 at 08:22

Yep, the acetaldehyde is definately reacting with the presious benzaldehyde thats fored in the reaction with cinnamon oil in boiling water with ph 12 as illustrated in point 2)

http://web.pdx.edu/~wamserc/CH332W97/homework/H11ans.htm

CycloKnight - 17-2-2012 at 06:15

Quote: Originally posted by questions  
I love benzaldehyde, not just for it's broad uses, but because of it's signature smell and oily texture, it's also very expensive in australia as well I hear.

I've been doing a lot of research into the reaction of cinnamon aldehyde in a boiling solution of water with ph 11 to 13 and antifoaming agent. I know this thread is all about toluene but I'm posting it here because more people ot at this thread, also cyclonight made many posts and no one knocked him for doing so.

Anyway, I've tried the experiment and have found that the more benzaldehyde is made, the more tar is formed in the reaction.
After an 7 hour reaction of 200ml of cinnamon aldehyde in a 2L solution of boling water with a steady ph of 12.5 and antifoaming agent, only 30% was benzaldehyde, 20% was unreacted cinnamon and the other 50% was all this tar shit.

I think that the aceteldehyde is reacting with the benzaldehyde in this base solution and that is what is making all this tar shit. Because I don't believe that this tar shit is a product of the cinnamon turning into benzaldehyde and acetaldehyde, I think that shortly after the benzaldehyde has formed, it reacts with the acetaldehyde that has formed. I cant think of any other explanation and I certainly dont think that the benzaldehyde is reacting with the cinnamon, could it????

If it is such that the formed benzaldehyde is reacting with the formed acetaldehyde, what can we put in place to stop or even minimise this from happening?


Hey mate,
been quite a while since I did this reaction, but I recall it quite well. You seem to be getting an awful lot of tar, might I ask how much steam you are putting through the reaction vessel? Was the cinnamonaldehyde pre-vacuum distilled prior to use or it it straight cinnamon bark oil?

As mentioned in PM, I made about a litre of refined, vacuum distilled benzadehyde in a few days, using not much more than a litre of cinnamonaldehyde, maybe 1.25 litres or so.
I didn't experience anywhere near the level of tar you've observed.
The benzaldhye WILL turn into tar if left stagnant in the pH 12 reaction vessel, this is why a large volume of steam is required, the steam removes the benzadehyde almost immediately as it is formed. However, no tar was produced in the condensate vessel where condensate, acetaldehyde, benzaldehyde and unreacted cinnamonaldehyde collected together.
I recall that for each 200 ml or so batch of cinnamonaldehyde, I put enough steam to condense into about a gallon of condensate (well, I used a 1L volumetric flask, filled about 4.5 times). Each 1 L volumetric flask was solvent extracted to recover the goods, but a large percentage of the aldehde was either sitting on the surface or would sink depending on the ratio of cinnamon to benzaldehyde. I recall that for each 1L flask of condensate fully filled, before solvent extracting, about an inch or two of free aldehyde would sit in the narrow neck, sometimes sinking if shaken.

The pooled solvent extracts where combined, DCM boiled off, then vacuum distilled to yield ~80% overall yield of benzaldehyde. Don't recall exactly, but it was around that mark - yields were very good.
Unreacted cinnamonaldehyde was recycled (this was the left over from the vacuum distillation).
To decide on the cinnamon aldehyde drip rate, match the drip rate with the rate of steam generation.
In other words, (for example) if it takes 4 hours to produce a gallon of condensate, then drip your 200 ml into the boiling hot pH 12 solution over 4 hours. The faster the rate of steam generation (and shorter reaction time) the better. I used a converted pressure cooker, which produced enough steam to limit each batch to a few hours. The reaction and steam distillation is finished when the condensate no longer smells of aldehyde, which isn't long after the last drop of cinnamonaldehyde is dripped into solution. Can't quick recall the mass flow rate I used, but I can tell you it was the maximum that would be allowed before the steam carried over bubbles and solution into the vigreux column, at times the bottom of the column would get wetted with bubbles, but would all separate before reaching the top (so as not to contaminate the condensate). The steam flow will be high enough to make the solution very turpid and noisy, it will cause the table top to vibrate as the bubbles knock the solution around quite a bit, just as if you inserted a straw and blew as hard as you could - that's the level of steam flow you need. :)
The only way I could get that level of flow without it shaking the equipment to pieces, was to take a glass tube about 10" long, heat the end to redness, and bend it into a fish hook shape (but taking care not to block the end). This causes the steam to flow UPWARDS, from the *bottom* of the solution. Fascilitating a nice flow, whereas simply putting a straight glass tube doesn't work too well.

Ck









questions - 24-2-2012 at 06:47

Cyclonight is clearly the most intelligent person on this site.

Antoncho - 2-4-2012 at 06:36

I had performed so many unsuccessful trials with persulfate oxidation of toluenes that now that I've succeeded I feel obliged to share :)

The procedure is somewhat of an arithmetic average of two patents, US4146582 and US7273954.


Apparatus:

500 ml three-necked flask
addition funnel
mechanical stirrer made of a car window raiser's motor (take a note of this fact, such a motor makes the most perfect mech stirrer that a hobby chemist can only dream of)
water bath


Reagents:

30 mls (244 mmole) p-xylene
100 mls DMSO
cupric acetate monohydrate 4.5 mmole in 10-15 mls water
ferrous sulfate heptahydrate (gardening grade) 1.5 mmole

Temp. raised to 70 C and with intensive mechanical stirring 128 g (561 mmole, 2,3 eq.) of ammonium peroxodisulfate (NH4)2S2O8 in 180 mls water was dripped in during 2 hrs, keeping the inner temperature at 70 C (the rxn is exothermic, the bath's temp. needed to bee kept at 60-63 C). Stirring continued for another hour after the addition was finished.

The RM was chilled well, saturated w/salt and xtracted with 4*50 mls EtOAc. Extracts washed with 10 mls 5% NaOH, then brine, diluted w/50 mls IPA, combined with 150 mls saturated aq. Na2S2O5 anв 10 g Na2S2O5 powder. With intensive mech stirring the temp. was raised to 45 C during 30 mins. The lower aq. layer was discarded and upper floating layer of precipitated adduct was filtered (filtration was nice and easy), washed on filter with 3*25 mls IPA dried and weighed (51 g).

The adduct was dissolved in 200 mls hot water, quenched with a slight xcess aq. NaOH and pH was carefully brought to weakly alkaline with dilute HCl (this is to aid the extraction, which is otherwise a mess). The mixture was cooled, saturated with NaCl and xtracted with 3*50 mls DCM. Extracts washed w/brine, dried, solvent removed on waterbath.

The yield was good 19.5 mls (67%) of para-tolualdehyde, which was almost colorless (!) and distilled in vacuo almost wholly to leave but slight driplets with sulfidic smell.

All of the further manipulations with this aldehyde were also quite successful ;)



Greetings from HyperLab,

Antoncho

[Edited on 2-4-2012 by Antoncho]

[Edited on 2-4-2012 by Antoncho]

[Edited on 2-4-2012 by Antoncho]

[Edited on 2-4-2012 by Antoncho]

chucknorris - 20-4-2012 at 06:21

Ok I have been cooking some benzaldehyde stuff recently. First I just mixed 300 grams of toluene, 700 grams of 65% H2SO4 and 90 grams of MnO2 and stirred and heated it for a while and then distilled the stuff to the point the H2SO4-MnO2 - gunk turned pale brown. In the receiver flask there formed two layers. At the beginning only the upper layer distilled, but when I kept going, the lower layer began to form. I havent yet been able to determine what the lower layer actually is, but it doesnt burn and it boils at 100C and its oily and clear liquid, which will dissolve water. I have gained about 500ml of this stuff.

Both layers smell a bit of almond as an evidence of benzaldehyde existence. The upper layer obviously consists of toluene, possibly some water, and benzaldehyde(??). I concentrated it via distillation and yellow oily liquid was left in the pot, which has strong almond smell. Only some 10mls of it is being around.

Now the second procedure: put 1:1 molar ratio of sulfuric acid and manganese dioxide in pan, add a bit of water and boil the shit until white fumes appear, let it cool and then add 1:1 amount of toluene and enough sulfuric acid to dissolve all the solids remained from the 1:1mol mixture. I left this stuff react for 24 hours and a yellow layer separated over the mno2-h2so4-gunk. Then added lots of water for steam distillation and distilled up the stuff. First came off the upper layer with homogenous solution, but then the "heavy stuff" began to drip again, when the upper layer was completely distilled. Obviously this stuff that accumulates to the bottom of the receiver flask is some sort of sulframic or other stuff which forms with water, h2so4 and mno2 existence.

Ok, now I've got pots around with almond and toluene smelling shit which I want to separate the remainings of benzaldehyde off. I understand that this can be accomplished with sodium bisulfite which I will get next week. The process for me is unknown so far, but what I have read it simply requires putting excess bisulfite to form adduct with the benzaldehyde, then filter this solid shit off, washed with concentrated bisulphite water solution and then reformed with 10% sodium bicarbonate solution. Am I correct with this one?

I'm not definitely sure what the yields are or what the hell is actually going in the distillery but I'm gonna find it out soon. Luckily the H2SO4, MnO2 and toluene are quite cheap and OTC for me so a little lower yield of benzaldehyde is not that big problem.

AC electrolysis

learningChem - 23-4-2012 at 18:23

Just found this - I don't think it's been already mentioned (though I may be wrong)

ELECTEOLYSIS WITH ALTEBNATING CURBENT.

Electrolytic oxidation may be moderated by superimposing alternating current upon direct current . 0. Eeitlinger1 has shown that alternating current diminishes the overvoltage at the anode during electrolysis, and it is thus possible to prepare oxidation products which are not easily obtained by direct current only. Ethyl and propyl alcohols give aldehydes, whereas when oxidised with continuous current only, the principal product is the corresponding acid.

Prom toluene suspended in dilute sulphuric acid (density 1*22) it is possible to obtain benzaldehyde and benzoic acid if A.C. be superimposed upon D.C., whereas with D.C. only, the toluene is completely oxidised to carbon dioxide and water. Similarly p-benzaldehyde sulphonic acid is obtained from toluene sulphonic acid.

By the same method sulphuric acid may be made to yield a considerable quantity of ozone, whilst ammonia may be oxidised to nitrous acid (40 per cent, yield) without the formation of nitric acid.

These investigations indicate that we have here a valuable means of controlling oxidation processes.

1
Zeitsch. EleMrochem., 1014, 20, 261.

taken from THE MANUFACTURE OF CHEMICAL S BY ELECTROLYSIS (sciencemadness library)

Hilski - 25-4-2012 at 18:44

Quote: Originally posted by learningChem  
Just found this - I don't think it's been already mentioned (though I may be wrong)

ELECTROLYSIS WITH ALTERNATING CURRENT.

Electrolytic oxidation may be moderated by superimposing alternating current upon direct current . 0. Eeitlinger1 has shown that alternating current diminishes the overvoltage at the anode during electrolysis, and it is thus possible to prepare oxidation products which are not easily obtained by direct current only. Ethyl and propyl alcohols give aldehydes, whereas when oxidised with continuous current only, the principal product is the corresponding acid.

From toluene suspended in dilute sulphuric acid (density 1*22) it is possible to obtain benzaldehyde and benzoic acid if A.C. be superimposed upon D.C., whereas with D.C. only, the toluene is completely oxidised to carbon dioxide and water. Similarly p-benzaldehyde sulphonic acid is obtained from toluene sulphonic acid.

1
Zeitsch. EleMrochem., 1014, 20, 261.

taken from THE MANUFACTURE OF CHEMICAL S BY ELECTROLYSIS (sciencemadness library)

That's pretty interesting. The reference doesn't give any details on how to go about superimposing the AC over the DC though. Things such as voltage and current density, frequency etc are probably important here. I'm definitely going to look into this further. Has anyone else ever heard of this, or tried it?

questions - 25-4-2012 at 19:44

when disstilling benzaldehyde at atmospheric presure, approximately how much of it will be lost a it turns to benzoic acid?

SteveJones - 11-5-2012 at 18:31

Were I to attempt to make benzaldehyde, I would do this:

Toluene ------> benzyl bromide

This is a free radical halogenation obviously, keep an excess of toluene to minimise formation of di and trisubstituted toluene, you can always recover this and re-use it. No, you don't need a UV light source (though it would help), just keep it refluxing with a bright light source if possible until the red colour from the bromine disappears.

benzyl bromide -----> benzaldehyde

Treat the benzyl bromide with stoichometric (slight excess would be better) amounts of DMSO (dimethyl sulphoxide) and a stoichometric amount of weak base (slight excess would be better) of your choice (sodium carbonate should work just fine) in a high boiling point solvent at reflux (using toluene would make this a one pot synthesis). This reaction will release dimethyl sulphide as a by product, so make sure you do this outside and wash your glass with bleach. This is a Kornblum oxidation, for those of you who are interested. Yields are reported to be around 70% so this 2 step method should be a viable method of benzaldehyde production.

Please let me know how this goes if anyone decides to try it, free radical halogenations with bromine aren't actually as user unfriendly as with chlorine, so don't let that put you off.

[Edited on 12-5-2012 by SteveJones]

Hilski - 29-5-2012 at 10:23

I decided to break out the ol' manganous-ammonium alum the other day, and oxidized some toluene, just for the hell of it. The stuff had been sitting in a sealed ptfe bucket for probably two years, maybe more. I had completely regenerated the oxidizer before I stored it, and it looked exactly the same two years later as the day I stored it.
I'm still not sure why more people don't use this method, since its so easy. From about 1 gallon of 60% acid, saturated with the deep purple alum, (just a small bit of undesolved solids) and around 700ml of toluene (I like to use a big excess, for various reasons) around 325ml of distilled aldehyde was obtained in around 3 hours.
Those who can't make this work, simply aren't doing it right. It's that simple.
When it comes to chemistry, if I can make it work, them damn near anyone should be able to make it work.

http://www.sciencemadness.org/talk/viewthread.php?tid=6882


billrussel - 26-6-2012 at 03:02

i am hoping you can tell me, is manganese sulphate (monohydrate) used in the benzyldehyde electro reaction? or is it the tetra/pentahydrate?
and if it is the tetrahydrate, how do i convert the monohydrate to that? can i just add water? i dont realy understand the meaning of a hydrate. it seems to mean 100 differnet things depending on context. if someone could explain it i would be grateful.

also can you link me to the method of purifying benzldehyde using ammonia persulphate? i realy dont understand the process.

thankyou alot

Hilski - 29-6-2012 at 20:41

Quote:
i am hoping you can tell me, is manganese sulphate (monohydrate) used in the benzyldehyde electro reaction? or is it the tetra/pentahydrate?
and if it is the tetrahydrate, how do i convert the monohydrate to that? can i just add water? i dont realy understand the meaning of a hydrate. it seems to mean 100 differnet things depending on context. if someone could explain it i would be grateful.

also can you link me to the method of purifying benzldehyde using ammonia persulphate? i realy dont understand the process.

thankyou alot

Most of the MnSO4 you would get through the usual channels will be the monohydrate.

Ammonium persulfate isn't used in this process. It would oxidize benzaldehyde, so Im pretty sure it wouldnt be used in any purification process either.

http://en.wikipedia.org/wiki/Manganese%28II%29_sulfate

billrussel - 3-7-2012 at 05:51

@ hilski you didnt answer my question at all! my question is what was used in the reaction, not what you can and cant get. and your right. my mistake, i think i meant sodium bisulphite, the chemical that has been mentioned a few times in the purification of benzyldehyde or was it a differnet chemical?

Hilski - 9-7-2012 at 09:48

Quote:
@ hilski you didnt answer my question at all! my question is what was used in the reaction, not what you can and cant get

Really?
Quote:
Most of the MnSO4 you would get through the usual channels will be the monohydrate.

If I'd used anything different, I would have said so.

And yes, bisulfite can be used for purification via the addition product, hydrolysis with Na2CO3 solution, followed by steam distillation etc. etc.

Washing the toluene/aldehyde with water and Na2CO3 solution before vac distillation is enough. It's not really necessary to go through the extra purification steps in my opinion.

Lithium - 13-7-2012 at 22:48

sorry if this has already been mentioned, but i am not going through 20 pages of posts.

can you oxidise toluene with TCCA in water, instead of using all this valuable H2SO4.

proposed equations:

(CNO-Cl)3 + 3H2O ===> (CNO-H)3 + 3HOCl

2HOCl + C6H5CH3 ===> 2HCl + C6H5CHO + H2O

sorry for no references, i cant find the pdf, but i believe it is called something like "TCCA- a safe and efficient oxidant"

it showed many examples of oxidations in presence of water with TCCA

madcedar - 14-7-2012 at 10:56

You might find it in here: http://www.sciencemadness.org/talk/viewthread.php?tid=9336
and here:
http://www.sciencemadness.org/talk/viewthread.php?tid=1751



[Edited on 14-7-2012 by madcedar]

Hilski - 15-7-2012 at 12:38

Quote:
can you oxidise toluene with TCCA in water, instead of using all this valuable H2SO4.

No.

But TCCA can be used for producing benzylchloride from toluene.
https://www.sciencemadness.org/whisper/viewthread.php?tid=14...

Gas Mask

cal - 28-9-2012 at 18:51

Quote: Originally posted by Hilski  
Quote:
can you oxidise toluene with TCCA in water, instead of using all this valuable H2SO4.

No.

But TCCA can be used for producing benzylchloride from toluene.
https://www.sciencemadness.org/whisper/viewthread.php?tid=14...


I have done the TCCA with toluene and it is a serious vapor
problem and quite annoying. I am now trying the electrolytic
method even with my 300 cfm vent hood it poses a problem.:cool:

chucknorris - 26-11-2012 at 15:54

Is it possible to oxidize benzyl alcohol vapor with silver catalyst into benzaldehyde?

Gribo - 10-12-2012 at 01:34

Quote: Originally posted by chucknorris  
Is it possible to oxidize benzyl alcohol vapor with silver catalyst into benzaldehyde?


I would recommend using dilute nitric acid [1] instead. It is much easier then working with vapour...

===
[1] Joshi, S., & Kataria, K. (2005). Kinetics of Oxidation of Benzyl Alcohol with Dilute Nitric Acid. Industrial & engineering …, 325–333.

learningChem - 10-1-2013 at 12:04

As previosuly mentioned, toluene can be converted into benzaldehyde using MnO2. See for instance

http://www.google.com/patents/US613460

Reaction of toluene and MnO2 in ~60% sulphuric acid --> benzaldehyde.

Question : where does the O come from - what happens to the MnO2?

learningChem - 11-1-2013 at 20:26

2MnO2 + 4H+ + PhCH3 -> PhCHO + 2Mn+2 + 3H2O

2MnO2 + 2H2SO4 + PhCH3 --> PhCHO + 2MnSO4 + 3H2O

crapper - 24-1-2013 at 19:18

Quote: Originally posted by MeSynth  
100 mls., of aqueous phase, containing ferric sulphate (pFe=2), hydrogen peroxide (concentration 0.135 molar), and containing 1 gram. equivalent per liter of the acid stated in Table 4 below, were vigerously stirred with 100 mls. of toluene at 85C for 3 hours. Table 4 gives yield of benzaldehyde.

Nitric acid 74.5% yield
Hydrochloric acid 58.5% yield (what the?)
Sulfuric acid 55% yield

----------------------------------------Taken from US3531519

My main question is how much ferric sulphate is used? I do not comprehend (pFe=2) ?

If someone could help me figure out pFe=2 I would be greatful.


There is a pFe calculation in this file.


Attachment: 2008 test2key.pdf (53kB)
This file has been downloaded 1595 times

Nathaniel - 8-3-2013 at 23:40

I finnally got 1kg of manganese sulphate and can use it to oxidize toluene to benzaldehyde (electrolysis of MnSO4, H2SO4, (NH4)2SO4 )

What I'd like to know, if anyone can help me is a mechanism for the reaction, because I can't really imagine the methyl group to react so readily, being quite unreactive... The problem is that I don't have pure toluene and will have to get it from a paint thinner (40% toluene, 10% alkanes-C6-C11, the rest is acetone). The alkanes are almost impossible to remove from toluene and I've been wondering if they're gonna be oxidized as well? I really doubt that since they're very unreactive generally but if toluene is oxidized by the reagent perhaps so could be the alkanes?
I know the question is a bit silly but I'd like to be sure everything goes smoothly :)


 Pages:  1  ..  3    5    7